Aluminum cylinder heads generally include sintered powder metal valve seat inserts in order to provide sufficient durability. Occasionally, the valve seat inserts must be properly installed into the cylinder head. An improperly installed valve seat insert will leave a gap between the aluminum cylinder head and the sintered powder metal valve seat insert. If the gap exceeds a threshold value, the valve seat insert will insufficiently line the aluminum cylinder head. Eventually, the cylinder head around the gap near the valve seat insert will fail, requiring expensive repair. Currently, there is no way of quickly measuring the size of the gap between the valve insert and the aluminum cylinder head.